Then i used the 3V3 pin on the Arduino to get the 3.3V, and then i connected everything as shown.Then i programmed the Arduino using the example code, and when it was programmed nothing happend!The LCD was only Purple and hummed very much (caused by the backlight StepUp converter)

I have tried to find the problem, but I can't!If i disconnect the LCD and the I/O lines from the Arduino, and then connect to test the voltage deviders, the output is 3.25-3.27V when I apply 5V - so no problem there!

KioseusZnook

I've only had a quick read and it's hard to grasp from your words what you've done already so I may be wrong here; as you're now using two separate power supplies (the external 3V3 and the Arduino's 5V) in the same circuit have you connected both of their GND (0V) rails together?

Even though my application uses a slightly different LCD Module, nevertheless I thought I give you this hint - it might get you a step further.The Nokia 6610 (from nuelectronics.com) works only with the ARDUINO IDE 0011.More details about this project here at:http://www.halo-photographs.com/remote-shutter-release-timer/.